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what is the range of cosx\cos{\sqrt{x}} where .{.} represents fractional part

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Q. what is the range of cosx\cos{\sqrt{x}} where .{.} represents fractional part
  1. Cosine Function Range: The range of the cosine function, cos(θ)\cos(\theta), for any real number θ\theta is always between 1-1 and 11, inclusive. This means that for any input value, the output of the cosine function will be within the interval [1,1][-1, 1].
  2. Fractional Part Function: The fractional part function, x{x}, returns the fractional part of xx, which is xxx - \lfloor x\rfloor, where x\lfloor x\rfloor is the greatest integer less than or equal to xx. The range of the fractional part function is [0,1)[0, 1), meaning it includes 00 but does not include 11.
  3. Behavior on Interval: Since the fractional part of x\sqrt{x} is always between 00 and 11, and cosine is a periodic function with period 2π2\pi, we need to consider how the cosine function behaves on the interval [0,1)[0, 1) to determine the range of cosx\cos{\sqrt{x}}.
  4. Range Calculation: The cosine function is decreasing on the interval [0,π2][0, \frac{\pi}{2}]. Since π2\frac{\pi}{2} is approximately 1.571.57, which is greater than 11, the interval [0,1)[0, 1) falls within the decreasing part of the cosine function's first period.
  5. Final Range: Because the cosine function is decreasing on [0,π2][0, \frac{\pi}{2}] and the fractional part of x\sqrt{x} will never reach 11, the range of cosx\cos{\sqrt{x}} will be from cos(0)\cos(0) to cos(1)\cos(1), since cos(1)\cos(1) is less than cos(0)\cos(0) due to the decreasing nature of the function in this interval.
  6. Final Range: Because the cosine function is decreasing on [0,π2][0, \frac{\pi}{2}] and the fractional part of x\sqrt{x} will never reach 11, the range of cosx\cos{\sqrt{x}} will be from cos(0)\cos(0) to cos(1)\cos(1), since cos(1)\cos(1) is less than cos(0)\cos(0) due to the decreasing nature of the function in this interval.Calculating the values, we have cos(0)=1\cos(0) = 1 and cos(1)\cos(1) is approximately x\sqrt{x}00. Therefore, the range of cosx\cos{\sqrt{x}} is from approximately x\sqrt{x}00 to 11.